Stacking connection and locking device therefor

ABSTRACT

A stacking connection for pallets including a target and plug arrangement. The target is formed to center the plug, and includes a hole through which a portion of the plug may extend to enhance the stacking connection and inhibit separation of the connection when the pallets are subject to forces accidentally encountered. A locking device is provided for the stacking connection to further inhibit vertical separation.

[451 Jan.9, 1973 am e on m m SMS 9 1 9 l l 7 STACKING CONNECTION AND LOCKING DEVICE THEREFOR [75] Inventors: Richard W. Smedley, Joliet; Earl J.

,637,628 8/1927 Weisgerber. 2,469,516 5/1949 Pearson.......

Mack, Coal City, both of 111.

3,121,583 2/1964 Damm.........

[73] Assignee: Cerco Corporation, Joliet, 111.

July 8, 1970 Primary Examiner-Francis K. Zugel [22] Filed:

Assistant ExaminerPeter A. Aschenbrenner AttorneyKinzer, Dorn and Zickert [21] Appl. No.: 53,114

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....285/27 1 108/53 X 19 Claims, 16 Drawing Figures 2,673,700 3/1954 Eberhardt.......................,..

785,420 3/1905 Grigsby....... 2,733,828 2/1956 Averill PATENTED'JAM 9 ma SHEEI 1 OF 5 FIG.5

INVENTORS RICHARD W. SMEDLEY EARL J. MACK ATTORNEYS PATENTED JAN 9 I975 SHEET 2 [IF 5 INVENTORS RICHARD W. SMEDLEY EARL J. MACK ATTORNEYS PATENTED JAN 9 I975 SHEET 3 OF 5 INVENTORS RICHARD W. SMEDLEY EARL J. MACK Al' TURN LYS PATENTEDJAH 9 197a SHEET 8 [1F 5 INVENTORS RICHARD W. SMEDLEY EARL J. MACK ATTORNEYS PATENTED JAN 9 I875 SHEET 5 OF 5 INVENTORS RICHARD W SMEDLEY EARL J. MACK W A TO RN EYS STACKING CONNECTION AND LOCKING DEVICE THEREFOR This invention relates in general to a stacking connection for pallets, racks and other similar equipment, and to a locking device for a stacking connection.

l'leretofore, it has been common practice to employ a plug and target stacking connection in the stacking pallet industry to facilitate stacking of one pallet on another. The plug and target may be separately fabricated pieces which are usually permanently attached to the pallet, removable post or end frame by a method such as welding, or they may be formed as an integral portion of these items. The target is formed to provide initial guiding engagement by the plug although not perfectly aligned with the center of the target, wherein the target forms a centering operation as the plug enters into complete engagement thereof. This arrangement provides a practical stacking connection designed to speed up stacking operations. Yet, the safety of the stacking connection,'should the stack be inadvertently bumped or disturbed, is limited in that a given horizontal force will cause lateral shifting of the plug relative to the target and ultimate separation of the connection to disrupt the stack. It has been necessary for some users and manufacturers to eliminate the target in order to overcome the tendency to separate upon lateral shifting, but in doing so, the advantage of the self-centering target is lost, thereby making it' difficult and time consuming to effect the stacking operation. Moreover, there has not been heretofore provided any satisfactory method or means of preventing separation of a target and plug stacking connection as the result of vertical forces on a pallet.

The 'present invention provides a simple and inexpensive target and plug arrangement that obviates the difficulties heretofore known, wherein a hole or opening is formed in the bottom of the target to define a socket for receiving a part of the plug, thereby allowing better coaction between the target and plug in the stacking connection, and negating separation caused by a horizontal force or necessitating a substantially greater horizontal force to effect separation. The cost of this improvement is essentially negligible and maybe formed by drilling, punching or otherwise forming'a hole in the target.

Further, the present invention includes a locking device usable on the plug and target arrangement of the invention or the plug and target arrangement heretofore known to prevent vertical separation of a stacking connection.

It is therefore an object of the present invention to provide a new and improved stacking connection for pallets and the like.

Another objectof the present invention is in the provision of a target and plug stacking connection for pallets and the like which includes the formation of a socket in the base of the target for receiving a part of the plug to enhance the stability and rigidity of the stacking connection, wherein the socket is formed by providing a hole in the target.

A still further object of this invention is in the provision of a locking device for a plug and target stacking connection used with pallets and the like.

Another object of this invention is in the provision of a locking device for a plug and target stacking connection to prevent vertical separation, wherein the locking device may be easily and quickly applied to the stacking connection, and wherein the locking device may also be provided with means for preventing its inadvertent removal from the stacking connection.

Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts, in which:

FIG. I is a perspective view showing a plurality of pallets arranged in a stack and having plug and target stacking connections;

FIG. 2 is a perspective, partially exploded, view of a stacking pallet having removable corner posts;

FIG. 3 is a perspective, partially exploded, view of a stacking pallet having removable end frames;

FIG. 4 is an enlarged fragmentary view of a stacking connection illustrating the prior art plug and target arrangement, and showing some parts in vertical section;

FIG. 5 is a view similar to FIG. 4, but illustrating the plug and target stacking connection of the invention and showing some parts in vertical section;

FIG. 6 is a further enlarged plan view of a target for a plug and target stacking connection according to the invention;

FIG. 7 is a perspective view of a locking device for use with a plug and target stacking connection such as the type of the present invention, or that of the prior art, to prevent vertical separation of a stacking connection; 1

FIG. 8 is a view similar to FIG. 5, and illustrating a locking device in position on the plug and target stacking connection of the invention;

FIG. 9 is a perspective view of a modified locking device according to the invention which includes an arm pivotally mounted to insure against accidental removal of the device from a stacking connection; t

FIG. 10 is a view similar to FIG. 9 but illustrating the arm pivoted in a partially open position;

FIG. I l is a transverse sectional view taken through a stacking post and looking down on a stacking connection utilizing the locking device of FIGS. 8 and 9;

FIG. 12 is a front elevational view of the locking device of FIGS. 9, l0 and II and illustrating the arm in' a partially open position;

FIG. 13is a view similar to FIG. 11 but illustrating a modification, wherein the pivotal arm extends only partly over the post;

FIG. 14 is a view similar to FIG. 11 but illustrating a modification wherein the pivotal arm engages the target edge;

FIG. l5 is a perspective view of a stacking connection having the locking device of FIG. 14; and

FIG. 16 is a perspective view of a further modified locking device according to the invention.

Referring now to the drawings, and particularly to FIG. I, the use ofa plug and target stacking connection is illustrated where a plurality of pallets 15, 16, I7, 18 and 19 are stacked one above the other thereby increasing the storage capacity for a given floor space. Each pallet usually includes a rectangular frame 20, preferably of tubular material arranged to define a support for a plurality of boards or slats 21 to present a platform onto which goods may be placed.

At the four corners of the frame, stacking posts 22 are provided which project mostly above the frame 20 and slightly below the frame 20. The posts 22 may be solid, sectionally as shown in FIG. 2, part of removable end frames as shown in FIG. 3, or part of removable side frames, the latter not being shown but being like the end frames except being arranged along the sides of the main frame. From this, it should be appreciated targets may be mounted on the lower ends of the posts while the plugs may be mounted on the upper ends if so desired. The targets coact with the plugs to facilitate the alignment of one pallet on another and stacking through the corner posts, in that the target serves as a centering device for the plugs and eliminates the necessity for exact post alignment prior to engagement between the plugs and targets. Pallets in stacked position thereby are supported one above the other by virtue of the corner posts.

Heretofore, stacking connections having plug and target arrangements have taken the form shown in FIG. 4, wherein a plug 26 is attached to or formed at the lower end of a post 27, and a target 28 is attached or formed at the upper end of a post 29. The posts are in the form of tubing, and therefore hollow, and while shown to be rectangular in cross section tubing, it should be appreciated that it could be round in cross section tubing or any other type of tubing. The target 28 includes a bottom wall 30 and upstanding therefrom, side walls 31 which are flared outwardly and terminate in lips 32 having a cross sectional dimension much greater than that of the posts and that of the plug 26 to thereby facilitate the stacking operation and the self-centering guiding of a plug into the center of a target. The plug 26 may include an upper portion 33 which telescopes over the end of the post 27, and a lower portion 34, somewhat in the form of a cylinder and having a cross sectional dimension substantially smaller than that of the upper portion. Upon the errgagement of the plug 34 with any of the walls 31 of the target 28, it will be appreciated that the plug will ultimately be centered as it is moved to seated position in the bottom of the target as shown in FIG. 4. However, it will be further appreciated that a horizontal force applied to the upper pallet may cause the plug to rise as it slides along the walls 31 of the target and ultimately become dislodged to disrupt the stack. In such a case, the stacking advantage is then lost and damage to goods may even be possible. Also, time may be' lost in restacking, and injury to persons may result. Accordingly, the safety of the prior art stacking connection is limited.

The stacking connection of the present invention is intended to overcome the difficulties of the prior art stacking connection, wherein the connection takes the form shown in FIG. 5 with a plug and target arrangem'ent. This connection similarly includes a plug 36 attached to the lower end of a stacking post 37, and a target 38 attached to the upper end of a post 39. The plug is shown as the same type as the prior art and includes an upper portion 40 telescoping over the end of the post 37 and a lower portion 41 sized cross sectionally smaller than the upper portion. The posts 37 and 39, representative of the posts of stacked pallets or the like, are illustrated as being rectangular in cross section tubing, although the cross sectional shape may be otherwise formed, as already noted. Accordingly, the upper portion 40 of the plug 36 is formed to matingly engage the end of the post 37, and thereafter be suitably attached such as by welding 42. The lower portion 41 is illustrated as being cylindrically formed, although it may be otherwise formed.

The target 38 is similar in shape to that of the prior art targets in that it includes a generally frusto-rectangular body 43, that also may be defined as being generally frusto-pyramidal. Accordingly, a side wall or side walls are provided with a sloping surface that extends upwardly and outwardly, the largestend of the target being away from the-post 39 and the post 39 being in engagement with the target near the smaller end. The upper ends of the walls terminate in a lip 44.

The target may be attached to the upper end of the post 39 by welding 45. At the base or bottom of the target, a hole or opening 46 defines a socket which matingly receives the lower portion 41 of the plug 36. While the hole 46 is shown to be circular in FIG. 6 to accept a circular plug, it should be appreciated it could be rectangular to accept a rectangular plug. It permits the plug to move deeper into the target, wherein the upper portion 40 engages the side walls of the target as shown in FIG. 5 when the upper pallet is in resting position on the lower pallet. In the stacking connection position, vertical surfaces of the plug lower portion 41 coact with vertical surfaces of the socket 46 to rigidify and stabilize the stacking connection. It can therefore be readily appreciated that a horizontal bump of the upper pallet will not dislodge the plug from the target and separate the stacking connection. However, such 'dislodgement is possible in the prior art. Accordingly, the self-centering feature of the heretofore known target is retained, while additionally, a locking arrangement is defined in the stacking connection not heretofore possible. Therefore, a positive locking arrangement is provided against separation of the stacking connection in the event of a horizontal force being applied to the upper pallet or any pallet in the stack.

In order to preclude vertical separation of the stacking connection where a plug and target are provided, a locking device 50, FIG. 7, may be used and easily slipped into position as shown in FIG. 8; This locking device includes a U-shaped body' 51 having a bight portion 52 and a pair of opposed legs 53. The bight portion 52 is straight and the legs 53 extend normal thereto. Preferably, each of the legs and the bight portion have a generally channel-shaped or angleshaped cross section that is essentially V-shaped, although in some cases the bight portion may be flat. As seen in FIG. 8, the legs 53 include a generally horizontally extending portion 54 and a downwardly and inwardly extending portion 55. The legs straddle the stacking connection, and the distance between the horizontal portions of the legs is such as to overlie the upper portion 40 of the plug 36 to prevent the plug from being withdrawn through the locking device when it is in position as shown in FIG. 8. The downwardly and inwardly extending portions 55 of the legs 53 overlie the lip 44 of the target 38 and a part of the side walls of the target to prevent the locking device from being vertically moved along the stacking connection. Therefore, the vertical movement of the upper post beyond the locking device is prevented by the engagement of the upper portion of the plug with the locking device.

It can readily be appreciated that the locking device 50 can quickly and easily be slid into position on a stacking connection to thereafter prevent separation. It should also be appreciated that by changing the dimensions of the locking device, it can be utilized with the stacking connections of the prior art such as shown in FIG. 4.

Moreover, in the event that the plug used on the end of the stacking post is not provided with an upper portion like that of the type illustrated in the drawings, as it may be formed integral with the post, any suitable type of collar or flange may be provided on the upper post to coact with the locking device in a stacking connection. Similarly, the target could be formed by suitably flaring the post end. Essentially, the portions 54 and 55 of the locking device define lock elements, while the target and plug define locking elements, all of which coact to guard against separation of the stacking connection.

The locking device embodiment of FIGS. 9, 11 and 12, generally designated by the numeral 60, differs from the locking device 50 only in that a latch or locking arm is added to guard against lateral shifting of the locking device along the stacking connection and accidental'dislodgement from the connection. In this respect, the locking device includes a U-shaped body having a bight portion 61, opposed parallel legs 62, which together enable straddling of the stacking connection such as shown in FIG. 11; Additionally, upstanding ears or flanges 63 and64 are provided on the free ends of the legs 62. A latch or arm 65 is pivotally mounted on the ear 63 by pin 66, and may be provided with a slot 67 at the other end to mate with a pin 68 extending from the ear 64. The arm 65 therefore extends across the open end of the U-shaped body, and as seen in FIG. 11, overlies the upper post 37 to prevent removal of the locking device from the stacking connection. Yet, the locking device may be easily removed by raising the arm 65 to an upright position to open the end of the U-shaped body and permit it to be withdrawn from the stacking connection. The pin mounting of the arm 65 to the ear 63 may be such as to allow free movement of the arm into locking position by gravity or a frictional arrangement necessitating movement by force where the arm will stay in any position into which it is moved. If desired, means could be provided for temporarily securing the free end of the arm 65 to the ear 64.

The locking device 70 shown in FIG. 13,,differs from that of the type shown in FIGS. 9 to 12 only in that the latch or locking arm 7] is shorter and extends only part way across the width of the post 37. This illustrates that there may be some installations where only a simple locking arm need be utilized to accomplish the desired purpose of temporarily holding the locking device in position on the stacking connection.

A modified locking device is shown in FIGS. 14 and 15, which differs from the locking device embodiments of FIGS. 9 to 13 only in that the locking arm 81, in locking position, overlies the lip of the target 38. Accordingly, the legs of the U-shaped body are slightly longer to enable mounting of the arm 81 on ear 82 through pin 83 so that the arm 81 when moved to locking position will overlie the edge of the target 38 as seen in both FIGS. 14 and 15. Again, the arm 81 may be mounted on the ear 82 so that it may fall by gravity to locking position, or it may bemounted so thatit will hold in any position by friction. The length of the arm 81 need only be long enough so that it has a portion that will sufficiently overlie the target to prevent accidental removal of the locking device from the stacking connection.

The locking device shown in FIG. 16 generally indicated by the numeral 72, while serving the same purpose as that of the devices shown in FIGS. 9 to 15 illustrates a still further variation. The locking device 72 includes upper and lower U-shaped plates 73 and 74 connected together by a vertically extending plate 75. The upper U-shaped plate 73 is adapted to straddle the upper post and be positioned above the enlargement of the upper post which herein illustrated constitutes the upper portion of the plug, while the lower U-shaped plate 74 has an opening adapted to straddle the lower post and be positioned below the enlargement of the lower post which is defined by the target. A latch or locking arm 76 pivoted on pin 77 on an ear 78 extending from the upper U-shaped plate 73 serves to overlie one side of the target and prevent lateral shifting of the locking device once it has been placed in position on a stacking connection. Preferably the arm will be mounted to the car 78 so that it will fall by gravity to locking position, it being held in unlocking position during installation of a stacking connection. However, the pin connection may provide a frictional arrangement where the arm will hold in any position.

This locking device may also be slid on or off the stacking connection in a manner similar to the other embodiments above described.

It will be understood that modifications and variations may be effected without departing from thescope of the novel concepts of the present invention, but it is understood that this application is to be limited only by the scope of the appended claims.

This invention is hereby claimed as follows:

1. In stacking pallets wherein each pallet includes a plurality of hollow vertically extending posts, a stacking connection defining positive self-alignment and interlocking relationship of the posts for rigid columnar loading, said connection comprising a plug and target arrangement for the posts including a target mounted on one end of each post of one pallet and a plug mounted on one end of each post of the other pallet, said target including a continuous wall sloping inwardly and defining at its outer free end an opening substantially larger than the hollow of the post and the cross section of the plug, an opening at the inner end of the target aligned with and of about the same size as the hollow of the post on which it is mounted defining a plug receiving socket, said plug having an upper portion attached to the end of the post upon which it is mounted and a lower portion of smaller cross section than the post and sized to penetrate the socket, enter the post and freely mate in the socket of the target and provide positive self-alignment, and'the cross section of the upper portion being larger than the socket and defining a support for the post and adapted to rest on the target continuous wall to provide rigid columnar loading and a stacking connection of such integrity as to resist separation when subjected to horizontal or tipping forces.

2. The combination as defined in claim 1, wherein the socket and plug lower portions include mating sides which confine the plug and prevent horizontal movement between the plug and target.

3. The combination as defined in claim l, and a locking device coacting with said target and said plug to lock the upper post with the plug to the lower post with the target.

4. The combination as defined in claim 3, and means on said locking device for preventing its removal from the target and plug.

5. In a stacking pallet having a supporting platform and a plurality of hollow posts extending above and below the supporting platform, stacking connection elements on the ends of said posts wherein an element on an end of a post of one pallet coacts with an element on an end of a post of another pallet in stacked aligned relationtherewith to define a stacking connection having positive self-alignment and interlocking relationship of the posts for rigid columnar loading, said stacking connection elements comprising a target mounted on the upper end of each post and a plug mounted on the lower end of each post, said target including a pyramidally shaped wall opening outwardly away from the end of the post and providing guiding movement for a plug, and an opening in the bottom of the wall of the target aligned with and of about the same size as the hollow of the post and defining a socket, and said plug having an upper portion telescoping over the end of the post and having a cross section larger than the socket so that it engages and rests on the pyramidal wall of the target, and a lower portion having a cross section smaller than the upper portion and sized to penetrate the socket, freely enter the post and matingly engage the socket .to provide positive selfalignment, wherein the stacking connection provides rigid columnar loading and such integrity as to resist separation when subjected to horizontal or tipping forces.

6. A locking device for locking together a stacking connection for pallets, wherein the stacking connection includes a plug mounted on one end of a stacking post and a target mounted on the other end of the stacking post, said target being inverted bell-shaped to guide the plug thereinto and defining a locking element, and means on the post adjacent the plug end protruding to define a locking element, said locking device having a U-shaped body and slidable onto the target and having means overlying the target locking element and the plug end locking element to prevent the plug from being removed from the target.

7. A locking device as defined in claim 6, and an arm mounted on the U-shaped body to at least partially close the open end to prevent the device from sliding off the stacking connection.

8. In a pallet having a supporting platform and a plurality of hollow posts extending above and below the supporting platform, a stacking connection comprising a target mounted on the upper end of each post and a plug mounted on the lower end of each post, said target including a frusto-rectangular body, the smaller end being mounted on the post and the opening thereof aligned with and of about the same size as the hollow of the post defining a socket, the larger end defining an opening substantially larger than the hollow of the post and facing upward and the opening thereof serving to receive a plug of a superposed pallet, said plug including a lower portionhaving a cross section penetrating the target and matable in and an upper portion sized larger than said socket and engaging the target body,

and a locking device for preventing separation of the stacking connection, said device comprising a U- shaped body having a bight portion and opposed parallel legs extending normal to said bight portion, said legs being formed to overlie the edges of the target and the edges of the plug upper portion.

9. The combination as defined inclaim 8, and means on the free end of one of said legs coacting with the stacking connection to prevent removal of the locking device therefrom.

10. The combination as defined in claim 9, wherein said means includes an arm pivotally attached to one of said legs.

1 1. The combination as defined in claim 10, wherein the arm is mounted so that when in looking position it overlies the upper post. 4

12. The combination as defined in claim 10, wherein the arm is mounted so that when in locking position it overlies the target.

13. A locking device for locking together a stacking connection for pallets, wherein the stacking connection includes a plug mounted on the lower end of a stacking post and a target mounted on the upper end of the stacking post, said target being inverted bell-shaped to guide the plug thereinto and projecting outwardly from the post, thereby defining a locking element on the upper end of the post, and said lower end of the post having means protruding to define a locking element, said locking device comprising a U-shaped body having lock elements coacting with said locking elements and slidable onto the stacking connection to prevent separation thereof.

14. A locking device as defined in claim 13, and an arm pivotally mounted on the body 'to at least partially close the open end once the device is positioned on a stacking connection to prevent removal therefrom.

15. A locking device as defined in claim 13, and pivotal arm means on said body movable between locking and unlocking positions coacting with the stacking connection to lock the locking device in place thereon.

16. A locking device as defined in claim 15, wherein the arm is mounted so that when in looking position it overlies a post of the stacking connection of superposed pallets.

17. A locking device as defined in claim 15, wherein the arm is mounted so that when in locking position it overlies the target of the stacking connection of superposed pallets.

18. A locking device as defined in claim l3, wherein said U-shaped body includes a bight portion and a pair 

1. In stacking pallets wherein each pallet includes a plurality of hollow vertically extending posts, a stacking connection defining positive self-alignment and interlocking relationship of the posts for rigid columnar loading, said connection comprising a plug and target arrangement for the posts including a target mounted on one end of each post of one pallet and a plug mounted on one end of each post of the other pallet, said target including a continuous wall sloping inwardly and defining at its outer free end an opening substantially larger than the hollow of the post and the cross section of the plug, an opening at the inner end of the target aligned with and of about the same size as the hollow of the post on which it is mounted defining a plug receiving socket, said plug having an upper portion attached to the end of the post upon which it is mounted and a lower portion of smaller cross section than the post and sized to penetrate the socket, enter the post and freely mate in the socket of the target and provide positive self-alignment, and the cross section of the upper portion being larger than the socket and defining a support for the post and adapted to rest on the target continuous wall to provide rigid columnar loading and a stacking connection of such integrity as to resist separation when subjected to horizontal or tipping forces.
 2. The combination as defined in claim 1, wherein the socket and plug lower portions include mating sides which confine the plug and prevent horizontal movement between the plug and target.
 3. The combination as defined in claim 1, and a locking device coacting with said target and said plug to lock the upper post with the plug to the lower post with the target.
 4. The combination as defined in claim 3, and means on said locking device for preventing its removal from the target and plug.
 5. In a stacking pallet having a supporting platform and a plurality of hollow posts extending above and below the supporting platform, stacking connection elements on the ends of said posts wherein an element on an end of a post of one pallet coacts with an element on an end of a post of another pallet in stacked aligned relation therewith to define a stacking connection having positive self-alignment and interlocking relationship of the posts for rigid columnar loading, said stacking connection elements comprising a target mounted on the upper end of each post and a plug mounted on the lower end of each post, said target including a pyramidally shaped wall opening outwardly away from the end of the post and providing guiding movement for a plug, and an opening in the bottom of the wall of the target aligned with and of about the same size as the hollow of the post and defining a socket, and said plug having an upper portion telescoping over the end of the post and having a cross section larger than the socket so that it engages and rests on the pyramidal wall of the target, and a lower portion having a cross section smaller than the upper portion and sized to penetrate the socket, freely enter the post and matingly engage the socket to provide positive self-alignment, wherein the stacking connection provides rigid columnar loading and such integrity as to resist separation when subjected to horizontal or tipping forCes.
 6. A locking device for locking together a stacking connection for pallets, wherein the stacking connection includes a plug mounted on one end of a stacking post and a target mounted on the other end of the stacking post, said target being inverted bell-shaped to guide the plug thereinto and defining a locking element, and means on the post adjacent the plug end protruding to define a locking element, said locking device having a U-shaped body and slidable onto the target and having means overlying the target locking element and the plug end locking element to prevent the plug from being removed from the target.
 7. A locking device as defined in claim 6, and an arm mounted on the U-shaped body to at least partially close the open end to prevent the device from sliding off the stacking connection.
 8. In a pallet having a supporting platform and a plurality of hollow posts extending above and below the supporting platform, a stacking connection comprising a target mounted on the upper end of each post and a plug mounted on the lower end of each post, said target including a frusto-rectangular body, the smaller end being mounted on the post and the opening thereof aligned with and of about the same size as the hollow of the post defining a socket, the larger end defining an opening substantially larger than the hollow of the post and facing upward and the opening thereof serving to receive a plug of a superposed pallet, said plug including a lower portion having a cross section penetrating the target and matable in and an upper portion sized larger than said socket and engaging the target body, and a locking device for preventing separation of the stacking connection, said device comprising a U-shaped body having a bight portion and opposed parallel legs extending normal to said bight portion, said legs being formed to overlie the edges of the target and the edges of the plug upper portion.
 9. The combination as defined in claim 8, and means on the free end of one of said legs coacting with the stacking connection to prevent removal of the locking device therefrom.
 10. The combination as defined in claim 9, wherein said means includes an arm pivotally attached to one of said legs.
 11. The combination as defined in claim 10, wherein the arm is mounted so that when in locking position it overlies the upper post.
 12. The combination as defined in claim 10, wherein the arm is mounted so that when in locking position it overlies the target.
 13. A locking device for locking together a stacking connection for pallets, wherein the stacking connection includes a plug mounted on the lower end of a stacking post and a target mounted on the upper end of the stacking post, said target being inverted bell-shaped to guide the plug thereinto and projecting outwardly from the post, thereby defining a locking element on the upper end of the post, and said lower end of the post having means protruding to define a locking element, said locking device comprising a U-shaped body having lock elements coacting with said locking elements and slidable onto the stacking connection to prevent separation thereof.
 14. A locking device as defined in claim 13, and an arm pivotally mounted on the body to at least partially close the open end once the device is positioned on a stacking connection to prevent removal therefrom.
 15. A locking device as defined in claim 13, and pivotal arm means on said body movable between locking and unlocking positions coacting with the stacking connection to lock the locking device in place thereon.
 16. A locking device as defined in claim 15, wherein the arm is mounted so that when in locking position it overlies a post of the stacking connection of superposed pallets.
 17. A locking device as defined in claim 15, wherein the arm is mounted so that when in locking position it overlies the target of the stacking connection of superposed pallets.
 18. A locking device as defined in claim 13, wherein said U-shaped body inCludes a bight portion and a pair of legs extending therefrom, each leg having a channel shaped cross section.
 19. A locking device as defined in claim 13, wherein said U-shaped body includes upper and lower U-shaped portions interconnected by a connecting portion, and means on one of said upper or lower portions to lockably prevent removal of the device from a stacking connection. 